An expedition team is headed for the Northwestern Hawaiian Islands to investigate whether coral in the area survived its first documented widespread bleaching, a phenomenon that could be linked to global warming.

The National Marine Fisheries' 220-foot Oscar Elton Sette left Honolulu for the Northwestern Hawaiian Islands Saturday with a team of 20 scientists that will investigate whether coral in the area survived its first documented widespread bleaching, a phenomenon that could be linked to global warming.

National Marine Fisheries via Associated Press

The shift from the coral's natural range of colors  including red, green and blue  to blanched, sheet-white stretches, was discovered during a monthlong expedition in September last year. It occurred when water temperatures off Pearl and Hermes Atoll, Midway Island and Kure Atoll rose just a few degrees  a significant increase for delicate coral reefs, which are among the most unspoiled in the world.

The change is not just one of aesthetics. Sea life that called the coral home deserted the reefs because of the conversion.

Coral can survive bleaching and the process could be a natural function of the area's reef habitat, said Russel Brainard, chief scientist for the National Marine Fisheries Service's Coral Reef Ecosystem Division, which is now en route to the northwestern isles.

But when scientists went back to briefly survey the area in December, the coral had still not recovered from the temperature change.

"The consequences could be very significant because we don't know how fast they recover," he said. "The jury's still out on whether they're going to recover. If they die, they'll be taken over by algae."

The area in question is the second largest such reserve in the world, and home to 69 percent of the nation's coral reefs

If a bulk  or even a good percentage  of the coral were to die in the bleaching, the elaborately connected ecosystem that surrounds the coral could collapse within three years, Brainard said.

The bleaching is the first of its kind documented in the area and could be linked to global warming, Brainard said. Weather satellites monitoring the area for 20 years registered a temperature peak last year, he said.

"If global things like this are occurring, then even the most remote places might not be as protected as we think," Brainard said. "We are observing the initial stages of what could be global warming, and there could be a change in the coral reefs in the Pacific.

"What we can do about it is a very challenging concern, and it requires us to understand what's going on much better than we do."

Some state coral biologists have said low levels of bleaching are normal in healthy coral reefs, especially during warmer summer months.

But Brainard said the bleaching was significant and did not appear to be a routine natural occurrence. No bleaching was reported from similar expeditions in 2000 or 2001.

The team of 20 scientists and 23 crew members traveling on a 220-foot National Marine Fisheries Service vessel left Honolulu July 12 and is expected to reach the reefs by the end of the month. The expedition is financed by the National Marine Fisheries Service. This is the third year the marine experts have traveled to the islands to survey the area's reefs and sea life.

Coral bleaching has increased worldwide over the past several decades, especially in Florida. The data moves some environmentalists to believe that coral reefs are headed for extinction.

Brainard said scientists in Australia believe much of the Great Barrier Reef  the nation's calling card natural resource  could be dead in less than 50 years.

The Northwestern Hawaiian Islands are made up of 10 mostly uninhabited islets and atolls extending 1,200 miles northwest of Kaua'i.

Commercial fishing is restricted in the area and only about six commercial boats frequent the islands.

The team will head to the Northern Marianas Islands and Guam after surveying the Northwestern Hawaiian Islands.